Apparatus for spinning-in yarn in a spinning machine

Abstract

A spinning device of a rotor spinning machine has a spinning rotor made of magnetically hard material, seated for rotation in an air chamber connected with an underpressure source. A stator includes at least two electromagnetic coils is arranged around the outer circumferential surface of the spinning rotor. The spinning rotor is made as a ring consisting of magnetically hard material and magnetized normal to the plane passing through the axis of the spinning rotor.

What is claimed is:  
     
       1. A spinning device for producing yarns from a plurality of individual fibers which advance along a path in a rotor spinning machine, comprising: 
       an air chamber centered along an axis and located along the path;  
       a stator having a body mounted in the air chamber and provided with an inward radial surface;  
       a ring-shaped rotor made of magnetizable material and mounted in the air chamber inside the stator, the ring-shaped rotor having a peripheral radial wall provided with an outer surface, which is opposed to the inward radial surface of the stator, and with an inner surface having a collecting groove, the inner surface defining an outlet aperture spaced downstream from the collecting groove and an inlet aperture spaced upstream from the collecting groove;  
       a plurality of coils wound in the body of the stator and energizable to produce a magnetic field acting on the ring-shaped rotor; and  
       a controller for controllably energizing the coils so that the stator produces a first magnetic force: displacing the ring-shaped rotor axially relative to the stator to an operative position, in which the outer surface of the ring-shaped rotor is spaced radially from the inward radial surface of the stator, and a second magnetic force acting on the ring-shaped rotor such that the rotor rotates about the axis in the operative position to guide individual fibers entering: the inlet opening toward the outlet opening via the collecting groove for producing the yarns.  
     
     
       2. The spinning device defined in  claim 1 , wherein each of the inlet and outlet apertures of the ring-shaped rotor has a respective diameter smaller than a diameter of a portion of the inner surface which is provided with the collecting groove. 
     
     
       3. The spinning device defined in  claim 1 , further comprising a draw-off trumpet located downstream from the collecting groove for drawing off the yarns twisted from the individual fibers which are collected in the collecting groove during rotation of the ring-shaped rotor. 
     
     
       4. The spinning device defined in  claim 3 , wherein the draw-off trumpet extends from the ring-shaped rotor into the air chamber through the outlet aperture. 
     
     
       5. The spinning device defined in  claim 3 , wherein the draw-off trumpet is mounted in the air chamber so that it is spaced axially from and located downstream from the outlet aperture. 
     
     
       6. The spinning device defined in  claim 3  wherein the draw-off trumpet is mounted in the air chamber so that it is axially adjustable relative to the collecting groove, the outlet aperture being dimensioned to be larger than an outer dimension of the draw-off trumpet. 
     
     
       7. The spinning device defined in  claim 1 , further comprising an underpressure source located downstream from the air chamber and in flow communication therewith for evacuating air entering the ring-shaped rotor via the inlet aperture simultaneously with the individual fibers. 
     
     
       8. The spinning device defined in  claim 1 , wherein at least one of the inner radial surface of the stator and the outer surface of the rotor is covered with a coating layer. 
     
     
       9. A spinning device for producing yarns from a plurality of individual fibers, comprising: 
       a stator extending along an axis and having an inward radial surface;  
       a plurality of coils wound in the stator;  
       a rotor mounted inside the stator and having a peripheral radial wall provided with an outer surface, which is opposed to the inward radial surface of the- stator, and with an inner surface having a collecting groove, the inner surface defining inlet and outlet apertures spaced axially from the collecting groove in opposite directions; and  
       a controller for sequentially energizing the coils so that when one coil is energized, the stator produces a first magnetic force displacing the stator and rotor axially relative to one another to an operative position, in which the outer surface of the rotor and the inward radial surface of the stator are spaced radially from one another, and when the other coil is energized, the stator produces a second magnetic force acting on the rotor such that it rotates relative to the stator to guide individual fibers entering the inlet opening toward the outlet opening via the collecting groove for producing the yarns.